Paging for a radio access network having pico base stations

ABSTRACT

Methods and apparatus provide paging control to a femto radio base station ( 28   fj ) of a radio access network ( 24 ). Paging to a femto radio base station ( 28   fj ) is controlled by maintaining a paging control database ( 46 ) of allowed user equipment units for which paging is permitted in a cell of a femto radio base station ( 28   fj ). The paging control database ( 46 ) is used to determine if a paging message for a target user equipment unit is to be forwarded to the femto radio base station. The database ( 46 ) thus serves to redefine the effective paging area by preferably including in the effective paging area only those femto radio base station for which the target user equipment unit is listed as a paging-allowed user equipment unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority of the following United States provisional patent applications (all of which are incorporated herein by reference in their entirety):

U.S. Provisional Patent Application 60/722,983, entitled “REDIRECTION OF IP-CONNECTED RBS TO THE CORRECT RNC”;

U.S. Provisional Patent Application 60/722,984, entitled “AUTOMATIC RNC SELECTION FOR IP-CONNECTED RBS”;

U.S. Provisional Patent Application 60/722,982, entitled FINE-GRAINED ACCESS CONTROL IN A WCDMA SYSTEM USING PICO BASE STATIONS”;

U.S. Provisional Patent Application 60/723,946, entitled “PAGING FOR A WCDMA SYSTEM USING PICO BASE STATIONS”;

U.S. Provisional Patent Application 60/728,780, entitled “AUTOMATIC BUILDING OF NEIGHBOR LISTS IN A MOBILE SYSTEM”; and

U.S. Provisional Patent Application 60/731,495, entitled “AUTOMATIC CONFIGURATION OF THE MACRO RADIO IN A PICO BASE STATION”.

This application is related to the following United States patent applications (all of which are incorporated herein by reference in their entirety):

U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1024), filed on even date herewith, entitled “REDIRECTION OF IP-CONNECTED RADIO BASE STATION TO CORRECT CONTROL NODE”;

U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1023), filed on even date herewith, entitled “RADIO NETWORK CONTROLLER SELECTION FOR IP-CONNECTED RADIO BASE STATION”;

U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1022), filed on even date herewith, entitled “ACCESS CONTROL IN A RADIO ACCESS NETWORK HAVING PICO BASE STATIONS”;

U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1019 filed on even date herewith, entitled “AUTOMATIC BUILDING OF NEIGHBOR LISTS IN A MOBILE SYSTEM”;

U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1004, filed on even date herewith, entitled “AUTOMATIC CONFIGURATION OF MACRO RECEIVER OF PICO RADIO BASE STATION”; and,

U.S. patent application Ser. No. 11/380,824, filed Apr. 28, 2006, entitled “DYNAMIC BUILDING OF MONITORED SET”.

BACKGROUND

I. Technical Field

This invention pertains to wireless telecommunications, and particularly to paging in a radio access network having pico or “femto” radio base stations.

II. Related Art and Other Considerations

In a typical cellular radio system, wireless user equipment units (UEs) communicate via a radio access network (RAN) to one or more core networks. The user equipment units (UEs) can be mobile stations such as mobile telephones (“cellular” telephones) and laptops with mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-included, or car-mounted mobile devices which communicate voice and/or data with radio access network. Alternatively, the wireless user equipment units can be fixed wireless devices, e.g., fixed cellular devices/terminals which are part of a wireless local loop or the like.

The radio access network (RAN) covers a geographical area which is divided into cell areas, with each cell area being served by a base station. A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each cell is identified by a unique identity, which is broadcast as system information in the cell. The base stations communicate over the air interface with the user equipment units (UE) within range of the base stations. In the radio access network, several base stations are typically connected (e.g., by landlines or microwave) to a radio network controller (RNC). The radio network controller, also sometimes termed a base station controller (BSC), supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks. The core network has two service domains, with an RNC having an interface to both of these domains.

One example of a radio access network is the Universal Mobile Telecommunications (UMTS) Terrestrial Radio Access Network (UTRAN). The UMTS is a third generation system which in some respects builds upon the radio access technology known as Global System for Mobile communications (GSM) developed in Europe. UTRAN is essentially a radio access network providing wideband code division multiple access (WCDMA) to user equipment units (UEs). The Third Generation Partnership Project (3GPP) has undertaken to evolve further the UTRAN and GSM-based radio access network technologies.

As those skilled in the art appreciate, in WCDMA technology a common frequency band allows simultaneous communication between a user equipment unit (UE) and plural base stations. Signals occupying the common frequency band are discriminated at the receiving station through spread spectrum CDMA waveform properties based on the use of a high speed, pseudo-noise (PN) code. These high speed PN codes are used to modulate signals transmitted from the base stations and the user equipment units (UEs). Transmitter stations using different PN codes (or a PN code offset in time) produce signals that can be separately demodulated at a receiving station. The high speed PN modulation also allows the receiving station to advantageously generate a received signal from a single transmitting station by combining several distinct propagation paths of the transmitted signal. In CDMA, therefore, a user equipment unit (UE) need not switch frequency when handover of a connection is made from one cell to another. As a result, a destination cell can support a connection to a user equipment unit (UE) at the same time the origination cell continues to service the connection. Since the user equipment unit (UE) is always communicating through at least one cell during handover, there is no disruption to the call. Hence, the term “soft handover.” In contrast to hard handover, soft handover is a “make-before-break” switching operation.

Other types of telecommunications systems which encompass radio access networks include the following: Global System for Mobile communications (GSM); Advance Mobile Phone Service (AMPS) system; the Narrowband AMPS system (NAMPS); the Total Access Communications System (TACS); the Personal Digital Cellular (PDC) system; the United States Digital Cellular (USDC) system; and the code division multiple access (CDMA) system described in EIA/TIA IS-95.

There are several interfaces of interest in the UTRAN. The interface between the radio network controllers (RNCs) and the core network(s) is termed the “Iu” interface. The interface between a radio network controller (RNC) and its base stations (BSs) is termed the “Tub” interface. The interface between the user equipment unit (UE) and the base stations is known as the “air interface” or the “radio interface” or “Uu interface”. In some instances, a connection involves both a Source and Serving RNC (SRNC) and a target or drift RNC (DRNC), with the SRNC controlling the connection but with one or more diversity legs of the connection being handled by the DRNC. An Inter-RNC transport link can be utilized for the transport of control and data signals between Source RNC and a Drift or Target RNC, and can be either a direct link or a logical link. An interface between radio network controllers (e.g., between a Serving RNC [SRNC and a Drift RNC [DRNC]) is termed the “Iur” interface.

The radio network controller (RNC) controls the UTRAN. In fulfilling its control role, the RNC manages resources of the UTRAN. Such resources managed by the RNC include (among others) the downlink (DL) power transmitted by the base stations; the uplink (UL) interference perceived by the base stations; and the hardware situated at the base stations.

Those skilled in the art appreciate that, with respect to a certain RAN-UE connection, an RNC can either have the role of a serving RNC (SRNC) or the role of a drift RNC (DRNC). If an RNC is a serving RNC (SRNC), the RNC is in charge of the connection with the user equipment unit (UE), e.g., it has full control of the connection within the radio access network (RAN). A serving RNC (SRNC) is connected to the core network. On the other hand, if an RNC is a drift RNC (DRNC), it supports the serving RNC (SRNC) by supplying radio resources (within the cells controlled by the drift RNC (DRNC)) needed for a connection with the user equipment unit (UE). A system which includes the drift radio network controller (DRNC) and the base stations controlled over the Tub Interface by the drift radio network controller (DRNC) is herein referenced as a DRNC subsystem or DRNS. An RNC is said to be the Controlling RNC (CRNC) for the base stations connected to it by an Tub interface. This CRNC role is not UE specific. The CRNC is, among other things, responsible for handling radio resource management for the cells in the base stations connected to it by the Tub interface.

Some operators are investigating the possibility of providing home or small area WCDMA coverage for limited number of users using a small radio base station (“RBS”), also called a “Femto RBS” and/or a “Home RBS” and/or “pico RBS” and/or “micro RBS” in some contexts. According to such investigation, the small RBS would provide normal WCDMA coverage for the end users (e.g., to a user equipment unit (UE)), and would be connected to the RNC using some kind of IP based transmission. The coverage area so provided is called a “femto cell” (to indicate that the coverage area is relatively small). Other terminology for a femto cell includes “pico cell” or “micro cell”, which is in contrast to a macro cell covered by a macro or standard radio base station (RBS).

One alternative for the IP based transmission is to use Fixed Broadband access (like xDSL, Cable etc.) to connect the home RBS to the RNC. Another alternative would be to use Wireless Broadband access (e.g. HSDPA and Enhanced Uplink; or WiMAX). FIG. 5 illustrates the two different backhaul alternatives in more detail. The first alternative is labeled “xDSL Backhaul” and the second alternative is labeled “WiMAX Backhaul”.

In general, ordinary WCDMA base stations (macro RBS) are able to connect to an RNC using IP-based transmission. Operator personnel, e.g., employees of an operator company which owns or maintains the macro RBS nodes and RNC nodes of the radio access network (RAN), typically install the macro RBS nodes. As part of the installation, the macro RBS is manually configured with IP addressing information (DNS name, Fully Qualified Domain Name, FQDN, or IP-address) of the RNC to which the macro RNC is to connect.

By contrast, a femto RBS is typically installed by the end user rather than the network operator. The end users are also able to move the Femto RBS geographically from place to place without the operator being able or willing to control relocation of the femto RBS. Such user-directed relocation requires that, wherever the Femto RBS is installed or located, it should connect to the correct RNC. A “correct RNC” or “preferred RNC” in this sense would be the same RNC that is controlling the overlaying macro cell of the radio access network (RAN).

When the femto RBS is used to enhance local coverage for example in a small or home office (SOHO) environment, it should be dedicated to the home or enterprise since the transmission towards the radio network controller node (and mobile core network) may be using transmission provided and paid by the home or enterprise itself. In such case the only terminals belonging to the SOHO or enterprise should be allowed to access the femto radio base stations.

In some situations the end user or SOHO purchases and possibly operates the femto radio base station. In some instances the femto radio base station may be a type of base stations that can only serve a limited number of end users. In situations in which there the femto radio base station has limited capacity or ability to serve a limited number of users, it is important that femto radio base station resources not be consumed with paging operations for absent or eligible end users.

Given the considerations explained above, and as explained further below, paging operations can play a role in gaining end-user acceptance for the femto radio base station concept.

Paging is normally performed between a mobile station (MS) (e.g., a user equipment unit (UE)) and the core network. Paging is usually based on a concept known as Location Areas in the circuit switched (CS) domain and a similar concept known as Routing Areas in the packet switched (PS) domain). In the circuit switched (CS) domain each Location Area is afforded a Location Area Identity (LAI), while in the packet switched (PS) domain each Routing Area is afforded a Routing Area Identity (RAI). Each MS/UE keeps track of the last LAI and RAI where it last successfully performed Location/Routing Area Update. The Radio Access Network (e.g. GERAN or UTRAN) broadcasts the LAI and RAI in the system information for each cell. A MS/UE can then compare this LAI/RAI with the previous one and, if these differ, the Location/Routing Area update procedures are triggered.

The core network keeps track of the MS/UE location on a Location (and Routing) Area level. This means that when a MS/UE terminating procedure is to be started, the network needs to normally page the MS/UE in the whole Location Area.

Thus, it is understood that Location (and Routing) Area planning is an important part of network configuration. Location (and Routing) Area planning vastly affects the network performance as, for example, in a large Location Area a MS/UE does not need to perform Location (and Routing) Area Updates very often. As a correlative disadvantage, however, the Paging Area is also very wide when the Location (and Routing) Area is large. In such case, one paging operation would need to be performed on multiple BSCs/RNCs and base stations/cells. On the other hand, a small Location Area means that a MS[UE will likely perform Location (and Routing) Area Updates more often, but in an inverse sense the magnitude of the paging operation is more optimized. However, in a femto system, the handling of Location (and Routing) Areas is totally different as the end users/femto operator installs the femto radio base station.

Paging handling is problematic and sorely lacking for a WCDMA system with femto radio base stations. The main reasons for the problems and perplexities are the following:

Preferably, in a WCDMA network, a macro cell coverage and a femto radio base station cell coverage does not have the same LAI/RAI. A distinct LAI/RAI identifier is needed for the femto cells compared to macro cells in order to provide reasonable access control for a femto radio base station and to assure that a MS[UE accessing a Femto-RBS will always initiate a Location Update towards the Core Network. Techniques of access control for a femto radio base station are described, e.g., in U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1022), filed on even date herewith, entitled FINE-GRAINED ACCESS CONTROL IN A WCDMA SYSTEM USING PICO BASE STATIONS”.

Preferably, paging for a MS/UE connected to a femto radio base station does not need to be sent to all femto radio base stations. Paging in all femto radio base stations of a MS[UE connected to one particular femto radio base station would create a vast amount of traffic on the backhaul part connecting the femto radio base station to the RNC and would degrade the total bandwidth available. The backhaul is also in some cases paid and provided by the end users and also used for other purposes.

It would initially seem that a simple solution to the paging dilemma would be to assign each femto radio base station its own LAI (and RAI). However, assigning a unique LAI and RAI to each femto radio base station is also problematic. For example, the maximum number of different LAIs for each Public Land Mobile Network (PLMN) is 65535. The number of LA identifiers that can be used for handling femto radio base station is less, as the same LAI space is also used in the macro network. In addition, assigning a unique LAI to each femto radio base station would impose large operation and maintenance (O&M) overhead (considerable more O&M tasks). Therefore LAIs/RAIs needs to be reused among the femto radio base stations.

What is needed, therefore, and an object herein provided, are method, technique, apparatus, or systems for providing effective paging control to a femto radio base station in a radio access network.

BRIEF SUMMARY

Methods and apparatus provide paging control to a femto radio base station of a radio access network, e.g., for determining in which femto radio base stations/cells to page a specific user equipment unit. Paging with respect to a femto radio base station/cell is controlled by maintaining a paging control database of allowed user equipment units for which paging is permitted in a cell of a femto radio base station. The paging control database is used to determine if a paging message for a target user equipment unit is to be forwarded to the femto radio base station.

The femto radio base station is typically controlled by a radio network controller node. Preferably the paging control database is configured to associate, for each of plural femto radio base stations controlled by the radio network controller node, a list of allowed user equipment units. For allowed user equipment units on the list paging is permitted in the cell(s) of the respective femto radio base station(s).

The paging message is first sent from the core network to the radio access network and typically includes a network area identifier (i.e. so called paging area) which is associated with plural femto radio base stations controlled by the radio network controller node. For example, in one implementation the network area identifier is associated with all femto radio base station controlled by the radio network controller node. In another implementation, a subset of radio base stations controlled by the radio network controller node consists of femto radio base stations, and the network area identifier is associated the subset of femto radio base stations.

In one of its aspects, the technology concerns methods of operating a radio access network. One of the methods includes (1) maintaining a paging control database which associates, for each of plural femto radio base stations, a list of allowed user equipment units for which paging is permitted in the cell of the respective femto radio base stations; (2) upon receiving a paging message for a target user equipment unit, using the database to redefine an effective paging area for the target user equipment unit; and (3) forwarding the paging message only to femto radio base stations which are included in the effective paging area. The step of using the database to redefine the effective paging area preferably comprises including in the effective paging area only those femto radio base stations for which the target user equipment unit is listed as a paging-allowed user equipment unit.

Another aspect of the technology concerns a radio access network comprising a femto radio base station for serving a femto cell of the radio access network; at least one radio network controller node configured for controlling the femto radio base station; and, a paging control database. The paging control database is configured for facilitating a determination whether a paging message received at the at least one radio network controller node for a target user equipment unit is to be forwarded to the femto radio base station. In one sense, the paging control database is configured for redefining an effective paging area for the target user equipment unit. The paging control database can be situated as a stand alone node of the radio access network or situated at a radio network controller node of the radio access network. Preferably the paging control database is configured for making the determination in response to interrogation by the radio network controller node.

Yet another aspect of the technology concerns a radio access network node comprising a paging control database configured for facilitating a determination whether a paging message received at a radio network controller node for a target user equipment unit is to be forwarded to the femto radio base station.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

FIG. 1A-FIG. 1E are diagrammatic views of an example embodiment of a telecommunications system including a radio access network, also illustrating example steps or events performed in conjunction with paging control.

FIG. 2 is a schematic view of an example embodiment of a femto radio base station.

FIG. 3 is a schematic view of a radio network control (RNC) node.

FIG. 4 is a diagrammatic view of an example structure of paging control database.

FIG. 5 is a diagrammatic view showing two different backhaul alternatives.

FIG. 6 is a diagrammatic view of example steps or events performed in conjunction with access control and paging control in a radio access network which comprises femto radio base stations.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

Thus, for example, it will be appreciated by those skilled in the art that block diagrams herein can represent conceptual views of illustrative circuitry embodying the principles of the technology. Similarly, it will be appreciated that any flow charts, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

The functions of the various elements including functional blocks labeled as “processors” or “controllers” may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared or distributed. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may include, without limitation, digital signal processor (DSP) hardware, read only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage.

The present invention is described in the non-limiting, example context of a telecommunications system 10 shown in FIG. 1A. The telecommunications system 10 connects to a core network 20. The telecommunications system 10 comprises a radio access network 24. The radio access network 24 includes one or more radio network controller nodes (RNCs) 26 and radio base stations (BS) 28. For sake of example FIG. 1A particular shows two radio network control nodes, i.e., a first radio network control 26 ₁ and a second radio network control 26 ₂ as well as one or more macro radio base stations (only one macro radio base station 28 _(M) being shown in FIG. 1A) and plural femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx). The macro radio base station 28 _(M) serves a macrocell C_(M). The femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx) serve respective femtocells C_(f1), C_(f2), . . . C_(fx). The person skilled in the art understands that a radio base station is typically situated at an interior (e.g., center) of the respective cell which the radio base station serves, but for sake of clarity the macro radio base station and femto radio base stations of FIG. 1A are shown instead as being associated by double headed arrows to their respective cells. At least some of the femtocells C_(f1), C_(f2), . . . C_(fx) are geographically overlayed or overlapped by the macrocell C_(M).

As used herein, a “femto radio base station” also has the meaning of a pico radio base station or a micro radio base station, which serves a femto cell (or pico cell or micro cell). The femto cell is typically overlaid by one or more macro cells and serves a smaller geographic area or subscriber constituency than a macro cell. The technology described herein has particular benefit for a femto radio base station which can be installed and/or relocated within a radio access network without the installation or relocation being controlled by the owner/operator of the radio access network. In other words, a non-network operator entity (a femto operator) can acquire the femto radio base station and situate the femto radio base station in accordance with the preferences of the femto operator.

A user equipment unit (UE), such as user equipment unit (UE) 30 shown in FIG. 1A, communicates with one or more cells or one or more base stations (BS) 28 over a radio or air interface 32. The user equipment unit can be a mobile station such as a mobile telephone (“cellular” telephone) and laptop with mobile termination, and thus can be, for example, portable, pocket, hand-held, computer-included, or car-mounted mobile device which communicate voice and/or data with radio access network.

The radio access network 24 shown in FIG. 1A can be, by way of non-limiting example, a UMTS Terrestrial Radio Access Network (UTRAN). In the UTRAN, radio access is preferably based upon Wideband Code Division Multiple Access (WCDMA) with individual radio channels allocated using CDMA spreading codes. Of course, other access methods may be employed. The nodes 26 and 28 are respectively termed the radio network control node and the radio base station nodes in view of the UTRAN example. However, it should be understood that the term radio network control and radio base station also encompasses nodes having similar functionality for other types of radio access networks. Other types of telecommunications systems which encompass other types of radio access networks include the following: Global System for Mobile communications (GSM); Advance Mobile Phone Service (AMPS) system; the Narrowband AMPS system (NAMPS); the Total Access Communications System (TACS); the Personal Digital Cellular (PDC) system; the United States Digital Cellular (USDC) system; and the code division multiple access (CDMA) system described in EIA/TIA IS-95.

The radio access network 24 is connected to core network 20 over an interface, such as the Iu interface for UTRAN. The core network 20 of FIG. 1A can comprise, among other things a Mobile Switching Center (MSC) node, a Gateway MSC node (GMSC), a Gateway General Packet Radio Service (GPRS) support node (GGSN), and a General Packet Radio Service (GPRS) Service (SGSN) node. Circuit switched (CS) network or packet switched (PS) network can be connected to core network 20.

For sake of simplicity, the radio access network 24 of FIG. 1A is shown with only two RNC nodes 26. Multiple radio network controller nodes (RNCs) may be provided, with each RNC 26 being connected to one or more base stations (BS) 28. It will be appreciated that a different number of base stations than that shown in FIG. 1A can be served by a radio network control 26, and that RNCs need not serve the same number of base stations. Moreover, an RNC can be connected over an Iur interface to one or more other RNCs in radio access network 24. The radio network controller node (RNC) 26 communicates over an interface Tub with the macro radio base station 28M. Further, those skilled in the art will also appreciate that a base station such as the macro radio base station 28 is sometimes also referred to in the art as a radio base station, a node B, or B-node. Each of the radio interface 32, the Iu interface, the Iur interface, and the Tub interface are shown by dash-dotted lines in FIG. 1A.

FIG. 1A further shows that the radio network controller nodes (RNCs) of radio access network 24 have access to femto paging control database 46. The femto paging control database 46 may be provided as a separate node of radio access network 24 as shown, or may be an adjunct of another RAN node (e.g., included in one or more radio network controller nodes (RNCs) 26). Alternatively, in certain cases, access to femto paging control database 46 can even be provided through core network 20. In the particular radio access network 24 shown in FIG. 1A, femto paging control database 46 is shown as being connected to radio network control nodes, and particularly to first radio network controller node RNC 26 ₁ and second radio network controller node RNC 26 ₂.

As shown by an example format depicted in FIG. 4, femto paging control database 46 maintains or lists allowed user equipment units for which paging is permitted in a cell of the respective femto radio base station. The paging control database is used to determine if a paging message for a target user equipment unit is to be forwarded to the femto radio base station. As shown in FIG. 4, femto paging control database 46 is formatted to list, for each of L number of femto radio base stations, identifications of the user equipment units which are permitted or allowed to be paged for the respective femto radio base station. An example such identification for a user equipment unit (UE) may be the International Mobile Subscriber Identity (IMSI) of the user equipment units.

FIG. 1A can be viewed as illustrating generic access of femto radio base station 28 _(fj) to the radio access network (RAN), e.g., to its radio network controller node (e.g., radio network controller node 26 ₁ in the specifically illustrated scenario). By “generic access” is meant that the access afforded to femto radio base station 28 _(fj) can be either broadband fixed access or broadband wireless (mobile) access (e.g., WiMAX) as described above. In broadband wireless (mobile) access, access for femto radio base station 28 _(fj) to the radio access network 24 is through a macro radio base station, and can occur using, e.g. High Speed Downlink Packet Access (HSDPA) and Enhanced Uplink; or WiMAX. To cater generically to the access types, in FIG. 1A the femto radio base stations 28 _(f) including femto radio base stations 28 _(fj) are connected to a communications network 38. An example of such communications network is an IP network 38. Unless otherwise specifically exempted in its context, aspects of the technology described herein are applicable to all types of access, including broadband fixed access and broadband mobile access (e.g., broadband wireless access).

FIG. 2 illustrates basic, selected, representative constituent elements of an example generic femto radio base station 28 _(f). One or more of the femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx) can take the form of the generic femto radio base station 28 _(f) shown of FIG. 2. The femto radio base station 28 _(f) of FIG. 2 is shown as including, among its other unillustrated constituent units, an interface unit 50 for connecting with radio network control node 26 over an interface; one or more radio frequency transceivers 52; and, a data processing system, section, or unit 56.

The interface between femto radio base station 28 _(f) and a radio network controller node can be, for example, the conventional Iub interface as shown in FIG. 1A. Alternatively or additionally, the interface between femto radio base station 28 _(f) and a radio network controller node can offer connectivity to/through an IP networkand utilize, e.g., Internet Protocol (IP)-based transmission.

The radio frequency transceivers 52 are for communicating over the radio or air interface with user equipment units (UEs) in the femtocell served by the femto radio base station 28 _(f). The number of radio frequency transceivers 52 depends on various factors including capacity of the femto radio base station to handle mobile connections.

FIG. 3 illustrates basic, selected, representative constituent elements of an example radio network control node 26. The radio network control node 26 can comprise several interface units, such as an interface unit 70 for connecting radio network control node 26 over the Iu interface to core network 20; an interface unit 72 for connecting radio network control node 26 over the Iur interface to other (unillustrated) radio network controllers; one or more interface units 74 for connecting radio network control node 26 over the Tub interface to respective one or more macro radio base station 28 _(M); and, one or more interface units 76 for connecting radio network control node 26 to respective one or more femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx). The connection between RNC 26 and its radio base station(s) can utilize, e.g., Internet Protocol (IP)-based and/or ATM-based transmission.

In addition to interface units, the radio network control node 26 comprises numerous unillustrated constituent units, as well as a data processing system, section, or unit 80. As shown in FIG. 3, in an example, non-limiting implementation the data processing system 80 of radio network control node 26 comprises a control section (e.g., controller 82); a handover unit 84; a combiner and splitter unit 86 (involved, e.g., in handling diversity legs of a connection); a femto radio base station handler 88; and, a paging handler 89. The femto radio base station handler 88 includes a searcher interface 92 for femto paging control database 46.

The particular radio network controller node 26 ₂ happens to control both macro radio base station 28 _(M) and femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx). According to one aspect of the technology, the radio network controller node 26 ₂ is associated with two network area identifiers: first network area identifier NAI_(26-M) for use with (e.g., in paging) the macro radio base stations (e.g., macro radio base station 28 _(M)) and a second network area identifier NAI_(26-f) for use with (e.g., in paging) the femto radio base stations (e.g., 28 _(f1), 28 _(f2), . . . 28 _(fx)). In this respect, for sake of illustration FIG. 1A shows the femto radio base stations (e.g., 28 _(f1), 28 _(f2), . . . 28 _(fx)) as being bounded by or enclosed in an area depicted by dashed lined labeled NAI_(26-f) and the macro radio base station 28 _(M) as being bounded by or enclosed in an area depicted by dashed line NAI_(26-M).

As a precursor to describing use of paging control database 46, it is useful to describe other preliminary operations of radio access network. At the time shown in FIG. 1A, user equipment unit (UE) 30 is seeking access to radio access network 24 via femto radio base station 28 _(fj). The femto radio base station 28 _(fj) has been activated by a femto operator and has been connected to a correct radio network controller node (e.g., radio network controller 26 ₂). The femto radio base station 28 _(fj) can become connected to is correct radio network controller node in various ways, such as those explained, e.g., in U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1022), filed on even date herewith, entitled “REDIRECTION OF IP-CONNECTED RBS TO THE CORRECT RNC”; and U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1023), filed on even date herewith, entitled “AUTOMATIC RNC SELECTION FOR IP-CONNECTED RBS”, both of which are incorporated herein by reference.

In seeking access to radio access network 24 via femto radio base station 28 _(fj), the user equipment unit 30 attempting to use femto radio base station 28 _(fj) for access to radio access network 24, as generically represented by event or step S-1A in FIG. 1A. One example way for user equipment unit 30 to attempt to use femto radio base station 28 _(fj) for access to radio access network 24 is by user equipment unit 30 attempting to establish a radio resource control (RRC) connection (RRC connection establishment) with radio access network 24 through femto radio base station 28 _(fj).

The actions of step S-1A of FIG. 1A and the area update procedure are further described (as sub-steps) with reference to FIG. 6. FIG. 6 shows, as sub-step S-1A-1, the candidate user equipment unit 30 trying to camp on the cell of femto radio base station 28 _(fj), and in so doing the candidate user equipment unit 30 detects a new network area identifier (e.g., a new LAI) broadcast in the cell C_(fj) of femto radio base station 28 _(fj). A new network area identifier is an LAI which is different than the previous LAI where a (location) updating procedure was successful. In particular, for the illustrated example, candidate user equipment unit 30 detects the network area identifier NAI_(26-f). As sub-step S-1A-2 user equipment unit 30 sends a RRC connection establishment message to radio network controller node 26 ₂ via femto radio base station 28 _(fj). The RRC connection establishment message of sub-step S-1A-2 includes identification information regarding the user equipment unit 30, e.g., the IMSI of candidate user equipment unit 30. As part of sub-step S-1A-2, femto radio base station 28 _(fj) relays the RRC connection establishment message over an appropriate interface (e.g., the Tub interface) to radio network controller 26 ₂.

Upon reception of the RRC connection establishment message of sub-step S-1A-2, radio network controller node 26 ₂, checks paging control database 46 to find out whether user equipment unit 30 is a permitted user/subscriber/customer of femto radio base station 28 _(fj). In this regard, the check/query message of sub-step S-1A-3 to femto paging control database 46 includes both the identifier of the user equipment unit 30 and an identifier of the femto radio base station 28 _(fj) for which permission is sought. Thus, in the context of sub-step S-1A-3, the paging control database 46 can also optionally serve as an access control data base. In terms of also optionally being an access control database, the database stores a list of allowed user equipment units which are to be permitted access for use of a femto radio base station. That is, the access control database is consulted and used to determine if a candidate user equipment unit attempting to use the femto radio base station for access to the radio access network is to be given access. Use of paging control database 46 as an access control database and access control for femto radio base station 28 _(fj) in general is described in more detail in U.S. patent application Ser. No. 11/______ (attorney docket: 2380-1022), filed on even date herewith, entitled “ACCESS CONTROL IN A RADIO ACCESS NETWORK HAVING PICO BASE STATIONS”. In the present scenario, it is assumed that candidate user equipment unit 30 is a permitted or allowed access to/via femto radio base station 28 _(fj), and accordingly an RRC connection establishment accepted message is sent as illustrated by sub-step S-1A-4 of FIG. 6.

In view of the fact that RRC connection has been approved and so notified, an area update operation is performed. By “area update operation” is meant, for example, either a Location Area Update (LAU) or a Routing Area Update (RAU), whichever is appropriate. If, for example, the user equipment unit is attached to the circuit switched (CS) domain of the core network 20, a Location Area Update operation is performed as depicted by sub-step S-1A-5A of FIG. 6. On the other hand, if the user equipment unit is attached to the packet switched (PS) domain of the core network 20, a Routing Area Update operation is performed as depicted by sub-step S-1A-5B of FIG. 6. As shown in FIG. 6, a Location Area Update operation is performed between user equipment unit 30 and a Mobile Switching Center (MSC) node; a Routing Area Update operation is performed between user equipment unit 30 and a SGSN node.

With an area update operation/procedure having been performed for user equipment unit 30, the radio access network is now in a position that user equipment unit 30 can be paged. FIG. 1B and FIG. 6 in fact illustrates a paging message for user equipment unit 30 being received as step or event S-1B. The paging message of step or event S-1B, which seeks to page user equipment unit 30 as its “target” or “paged” user equipment unit, can originate from, e.g., core network 20. The paging message further specifies the network area identifier (e.g., either the LAI or RAI) for the page, e.g.,

NAI_(26-f).

Upon receipt of the paging message of step S-1B, radio network controller node 26 ₂ checks with femto paging control database 46 to determine to exact which ones of the femto radio base stations of the network area NA1 _(26-f) are to be involved in the page, so that only the femto radio base stations to which the user equipment unit 30 has access will be paged. The femto radio base station handler 88 directs searcher interface 92 to prepare a query of paging control database 46 so that radio network controller node 26 ₂ can ascertain for which femto radio base stations in the area are eligible for paging user equipment unit 30. The query to paging control database 46 includes both the identifier of the paged or target user equipment unit 30 and the network area identifier for the area in which paging permission is sought.

In the above regard, steps S-1C of FIG. 1C and of FIG. 6 show radio network controller node 26 ₂ checking paging control database 46 and obtaining therefrom a list of femto radio base stations in network area NA1 _(26-f) which authorize or permit paging for user equipment unit 30. In this regard, for the example format of the paging control database 46 as shown in FIG. 4, the returned list includes the identifiers of those femto radio base stations which have the IMSI or other identifier of the target user equipment unit mapped thereto or associated therewith.

Step S-1D of FIG. 1D and FIG. 6 show the ensuing step or event of the paging message for target user equipment unit 30 being forwarded to the femto radio base stations which permit paging to user equipment unit 30. In the particular situation shown in FIG. 1D, for sake of easy of illustration only one femto radio base station is permitted for paging, i.e., femto radio base station 28 _(fj). It should be understood, however, that in other situations it is entirely possible or even likely that the user equipment unit 30 may be paged in two or more femto radio base stations. For example, the same femto owner/operator may operate two or more femto radio base stations, and grant access and paging eligibility status to user equipment unit 30 in all femto radio base station owned/operated by that femto owner/operator.

Step S-1E of FIG. 1E and FIG. 6 illustrate the paging message to the target user equipment unit 30 being broadcasted in the cell C_(fj) of femto radio base station 28 _(fj). If the page for user equipment unit 30 had been permitted in other femto radio base stations, the paging message for user equipment unit 30 would be broadcast in those other femto radio base stations as well.

Thus, in one sense, femto paging control database 46 is configured for redefining an effective paging area for the target user equipment unit. Rather than the paging area being the entire area NAI_(26-f) as originally specified in the paging message of step S-1B, as a result of performance of step S-1C the paging control database 46 redefines and actually decreases the size of the paging area to be only those cells for which paging to the target user equipment unit 30 is permitted (as specified by the table or listing of paging control database 46).

The paging control database 46 can be situated as a stand alone node of the radio access network 24 as illustrated in FIG. 1A-FIG. 1E, or (alternatively) situated at a radio network controller node of the radio access network. Preferably the paging control database is configured for making the determination in response to interrogation by the radio network controller node (as occurred as part of step S-1C discussed above).

The femto paging control database 46 can be pre-configured and/or dynamically configured with identities of allowed user equipment units for which paging is to be permitted access for use of the femto radio base station. In this regard, the femto radio base station 28 _(fj) is identified in the RNC and in femto paging control database 46 with an identifier such as (for example) a serial number or the like. The association between serial number and mobile subscriber identity (e.g., IMSI) is initially done, e.g. at a store or other release point at which the pico-base station is purchased or acquired by the pico/femto owner/operator. Furthermore, it is also possible for the femto/pico owner/operator of femto radio base station 28 _(fj) to define which mobile subscribers (e.g., which user equipment units (UEs) are able to access femto radio base station 28 _(fj). Such control of access (be it either remote, subsequent, and/or dynamic) can be achieved, e.g., using a web-based service, where the owner of the base station is first authorized and is then able to define the allowed or permitted mobile subscribes. The mobile subscribers are preferably identified using MSISDN number and then the service can map these values to the IMSI values of the user equipment units for use by the femto paging control database 46.

In the scenario described above with reference to FIG. 1A-FIG. 1E, the radio network controller node 26 ₂ has control of radio base stations including both macro radio base stations and femto radio base stations, with a subset of the radio base stations controlled by radio network controller node 26 ₂ consisting of the femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx). The radio network controller node 26 ₂ also has a first network area identifier for its macro radio base stations, and a different network area identifier for the subset of femto radio base stations 28 _(f1), 28 _(f2), . . . 28 _(fx). In other implementations, however, a radio network controller node may be dedicated to femto radio base stations (and thus control no macro radio base stations), and accordingly have a network area identifier which refers to all femto radio base stations under its exclusive control.

Thus, the technology restricts paging of a target user equipment unit only to those femto radio base stations desiring to provide paging services for that particular user equipment unit. Such dedication and exclusivity is especially important if, for example, the end users' own broadband connection is used for transmission between base station and RNC or if the end user has paid for a certain WCDMA air capacity in the femto RBS.

Thus, as one aspect of the technology, a paging control database is configured for facilitating a determination whether a paging message received at a radio network controller node for a target user equipment unit is to be forwarded to the femto radio base station. In one implementation, the paging control database is configured for actually making the determination.

Thus, in accordance with one aspect of the technology, a MS/UE that is trying to camp on a cell handled by a femto radio base station initiates a Location (and Routing) Area Update towards the core network 20 (via the RNC/RBS or BSS). The RNC (or RBS) can then apply access control at RRC connection establishment and decide which MS[UEs are allowed to camp on the femto radio base station. When the RNC (or RBS in some scenarios) receives a circuit switched or packet switched paging message from the core network 20, it can perform a database query to paging control database 46 to find out which femto radio base stations a MS/UE is allowed to use. Then paging is forwarded to only those femto radio base stations. This means that the Paging Area is decreased from all femto radio base stations to only those that a particular MS/UE is allowed to use.

The foregoing principle/method can also be applied for radio technologies other than WCDMA, which is illustrated only as an example. Other suitable technologies include but are not limited to GSM, CDMA, WiMAX etc. The technology has particular relevance of the aforementioned and conveniently described system and scenarios, but could also be applied in other cases and for other networks.

As another example implementation, a number of (e.g., plural) LAIs (and RAIs) is assigned in the RNC for all the femto radio base stations under its control. When a femto radio base station connects to the RNC, the femto radio base station is automatically assigned one of these LAIs. These LAI assignments can be, for example, in round-robin manner so that each LAI contains almost an equal number of femto radio base stations. An advantage of this particular implementation is that no further changes are needed in the network. The amount of unnecessary Paging traffic decreases also, but still a large number of Femto-RBSs needs to be paged when searching for a specific UE.

In the technology described herein, Paging Areas are decreased from all femto radio base stations to only those that a particular MS/UE is allowed to use. This means that no extra and unnecessary traffic is created on the backhaul between the femto radio base stations and the RNC.

In todays WCDMA systems, the Radio Resource Control (RRC) protocol is terminated in the RNC. RRC handles the Paging towards the MS/UE. In a future system the RRC or equivalent radio control protocol may be terminated in the actual base station. Thus, within the scope of the present technology is the fact that paging control database 46 may reside in or being queried from other nodes.

Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential. The invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements. 

1. A method of operating a radio access network comprising: maintaining a paging control database of allowed user equipment units for which paging is permitted in a cell of a femto radio base station; using the database to determine if a paging message for a target user equipment unit is to be forwarded to the femto radio base station.
 2. The method of claim 1, further comprising using the database to determine to which femto radio base station(s) a paging message should be forwarded.
 3. The method of claim 1, wherein the femto radio base station is controlled by a radio network controller node, and further comprising configuring the paging control database to associate, for each of plural femto radio base stations controlled by the radio network controller node, a list of allowed user equipment units for which paging is permitted in the cell of the respective femto radio base stations.
 4. The method of claim 1, wherein the femto radio base station is controlled by a radio network controller node, wherein the paging message includes a network area identifier, and wherein the network area identifier is associated with plural femto radio base stations controlled by the radio network controller node.
 5. The method of claim 4, wherein the network area identifier is associated with all femto radio base stations controlled by the radio network controller node.
 6. The method of claim 4, wherein a subset of radio base stations controlled by the radio network controller node consists of femto radio base stations, and wherein the network area identifier is associated the subset of femto radio base stations.
 7. A method of operating a radio access network comprising: maintaining a paging control database which associates, for each of plural femto radio base stations, a list of allowed user equipment units for which paging is permitted in the cell of the respective femto radio base stations; upon receiving a paging message for a target user equipment unit, using the database to redefine an effective paging area for the target user equipment unit; and, forwarding the paging message only to femto radio base stations which are included in the effective paging area.
 8. The method of claim 7, wherein the step of using the database to redefine the effective paging area comprises including in the effective paging area only those femto radio base station for which the target user equipment unit is listed as a paging-allowed user equipment unit.
 9. The method of claim 7, wherein the femto radio base station is controlled by a radio network controller node, wherein the paging message includes a network area identifier, and wherein the network area identifier is associated with plural femto radio base stations controlled by the radio network controller node.
 10. The method of claim 9, wherein the network area identifier is associated with all femto radio base station controlled by the radio network controller node.
 11. The method of claim 9, wherein a subset of radio base stations controlled by the radio network controller node consists of femto radio base stations, and wherein the network area identifier is associated the subset of femto radio base stations.
 12. A radio access network comprising: a femto radio base station for serving a femto cell of the radio access network; at least one radio network controller node, the at least one radio network controller node configured for controlling the femto radio base station; a paging control database configured for facilitating a determination whether a paging message received at the at least one radio network controller node for a target user equipment unit is to be forwarded to the femto radio base station.
 13. The apparatus of claim 12, wherein the paging control database is configured for facilitating a determination as to which femto radio base station(s) a paging message should be forwarded.
 14. The apparatus of claim 12, wherein the paging control database is configured to associate, for each of plural femto radio base stations controlled by the radio network controller node, a list of allowed user equipment units for which paging is permitted in the cell of the respective femto radio base stations.
 15. The apparatus of claim 12, wherein the paging message includes a network area identifier, and wherein the network area identifier is associated with plural femto radio base stations controlled by the radio network controller node.
 16. The apparatus of claim 15, wherein the network area identifier is associated with all femto radio base station controlled by the radio network controller node.
 17. The apparatus of claim 15, wherein a subset of radio base stations controlled by the radio network controller node consists of femto radio base stations, and wherein the network area identifier is associated the subset of femto radio base stations.
 18. The apparatus of claim 12, wherein the paging control database is situated as a stand alone node of the radio access network.
 19. The apparatus of claim 12, wherein the paging control database is situated at a radio network controller node of the radio access network.
 20. The apparatus of claim 12, wherein the paging control database is configured for making the determination in response to interrogation by the radio network controller node.
 21. A radio access network comprising: at least one femto radio base station, the at least one femto radio base station for serving a respective femto cell of the radio access network; at least one radio network controller node, the at least one radio network controller node configured for controlling the at least one femto radio base station and for receiving a paging message for a target user equipment unit; a paging control database configured for redefining an effective paging area for the target user equipment unit; and wherein the at least one radio network controller node is arranged for forwarding the paging message only to femto radio base stations which are included in the effective paging area.
 22. A radio access network node comprising a paging control database, the paging control database being configured for facilitating a determination whether a paging message received at a radio network controller node for a target user equipment unit is to be forwarded to the femto radio base station.
 23. The apparatus of claim 22, wherein the paging control database is situated as a stand alone node of the radio access network.
 24. The apparatus of claim 22, wherein the paging control database is situated at a radio network controller node of the radio access network. 